diff options
Diffstat (limited to 'src/lang/Prolog.java')
| -rw-r--r-- | src/lang/Prolog.java | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/src/lang/Prolog.java b/src/lang/Prolog.java index a890026..d744667 100644 --- a/src/lang/Prolog.java +++ b/src/lang/Prolog.java @@ -10,6 +10,7 @@ import java.io.Reader; import java.io.Writer; import java.util.EnumSet; import java.util.HashMap; +import java.util.IdentityHashMap; /** * Prolog engine. * @@ -78,7 +79,7 @@ public final class Prolog { protected long previousRuntime; /** Hashtable for creating a copy of term. */ - protected HashMap<VariableTerm,VariableTerm> copyHash; + protected final IdentityHashMap<VariableTerm,VariableTerm> copyHash; /** The size of the pushback buffer used for creating input streams. */ public static final int PUSHBACK_SIZE = 3; @@ -134,6 +135,7 @@ public final class Prolog { trail = new Trail(); stack = new ChoicePointStack(trail); hashManager = new HashtableOfTerm(); + copyHash = new IdentityHashMap<VariableTerm, VariableTerm>(); } /** @@ -153,7 +155,6 @@ public final class Prolog { if (pcl == null) pcl = new PrologClassLoader(); if (internalDB == null) internalDB = new InternalDatabase(); - copyHash = new HashMap<VariableTerm, VariableTerm>(); streamManager = new HashtableOfTerm(); if (features.contains(Feature.IO)) { |